Electrical What's inside a TFI module? (Gut pictures inside)

Trogdor

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Aug 30, 2018
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This is just for the curious like me that have wondered what's inside a TFI module and to see if there are any differences between manufactures. I have 6 TFI modules sitting on my workbench. Why do I have so many? I was chasing a distributor issue that turned out to be that my stock distributor had worn the shaft bushing that allowed the trigger wheel to contact the PIP. Anyhow, back to the different TFI modules I have:

  1. New Motorcraft replacement.
  2. Old Motorcraft, most likely original to the distributor.
  3. Generic Parts store replacement.
  4. A remote mount unit from a 7.5L F-350 (I'm going to try and make my own remote TFI one day).
  5. Module that came with a Cardone rebuilt distributor.
  6. Wells branded replacement.
As you can see they are all a little different inside. From looking at just how they are constructed, the Wells unit would probably be may favorite after and old Motorcraft unit. I like the way the connector pins are hooked up to the board, seems beefier than the other replacements. I would up breaking the cover on this one as it was really well bonded to the case. I don't know much of what is going on inside them so I can't really comment on board layout.

So now enough chit-chat and let's get to some pictures:

1. New Motorcraft replacement:
TFI 1 New Motorcraft.jpg


2. Old Motorcraft:
TFI 2 Old Motorcraft.jpg


3. Parts store replacement:
TFI 3 Parts store replacement.jpg


4. Remote TFI from F-350:
TFI 4 Remote unit.jpg


5. Module that came with the Cardone distributor:
TFI 5 Cardone.jpg


6. Wells branded replacement:
TFI 6 Wells.jpg
 
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Potomus Pete

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This is just for the curious like me that have wondered what's inside a TFI module and to see if there are any differences between manufactures. I have 6 TFI modules sitting on my workbench. Why do I have so many? I was chasing a distributor issue that turned out to be that my stock distributor had worn the shaft bushing that allowed the trigger wheel to contact the PIP. Anyhow, back to the different TFI modules I have:

  1. New Motorcraft replacement.
  2. Old Motorcraft, most likely original to the distributor.
  3. Generic Parts store replacement.
  4. A remote mount unit from a 7.5L F-350 (I'm going to try and make my own remote TFI one day).
  5. Module that came with a Cardone rebuilt distributor.
  6. Wells branded replacement.
As you can see they are all a little different inside. From looking at just how they are constructed, the Wells unit would probably be may favorite after and old Motorcraft unit. I like the way the connector pins are hooked up to the board, seems beefier than the other replacements. I would up breaking the cover on this one as it was really well bonded to the case. I don't know much of what is going on inside them so I can't really comment on board layout.

So now enough chit-chat and let's get to some pictures:

1. New Motorcraft replacement:
TFI 1 New Motorcraft.jpg


2. Old Motorcraft:
TFI 2 Old Motorcraft.jpg


3. Parts store replacement:
TFI 3 Parts store replacement.jpg


4. Remote TFI from F-350:
TFI 4 Remote unit.jpg


5. Module that came with the Cardone distributor:
TFI 5 Cardone.jpg


6. Wells branded replacement:
TFI 6 Wells.jpg
That's a lot going on inside there.....Very interesting thanks for the info. No wonder they cost a hundred bucks, and I wonder if they are handmade by small people with soldering guns
 
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2000xp8

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Aug 8, 2003
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That's a lot going on inside there.....Very interesting thanks for the info. No wonder they cost a hundred bucks, and I wonder if they are handmade by small people with soldering guns
Believe it or not, there really isn't much going on in there.
I've done quite a bit of minor board repair (have a pinball and arcade collection, if you don't fix them, you have to pay dearly and wait forever for someone else to) and that is probably about $5-$10 in parts (maybe even less).
Some things i've had to buy only come in packs of 100 for like $1. And that's pricing for "non bulk" purchases.

The reason they probably can't be repaired is that most guys handy with a soldering iron don't/can't do surface mount soldering (including me).

Kinda figures that they have gotten less reliable, the original's worked pretty well forever and then they changed the design...
 
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a91what

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SMD components can be done easily with a hot air gun and some solder wipe.. you can get a cheap-o solder station these days for under $100 on amazon.
You basically have 2 things happening in there... 1 is the circuitry that handles the pip, it is set so that it will fire the IGBT when the spout is removed at mechanical timing, very simple design it includes the trigger for the IGBT.
The IGBT is a high current device that can deal with the transient voltages associated with firing the coil [collapsing field ect] these are the expensive part [100 of them for a few bucks]
I actually designed a simple TFI replacement driver for the Mega-squirt crowd that even has CCD capabilities and its only 3 components lol.
 
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Bird76Mojo

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While you've got one gutted, might as well make your own remote mount TFI harness and switch to the SN95 style distributor.. It's easy.

Mine has held up well for over 20,000 miles so far, and it runs at ambient temperature. When it was on the distributor, I checked it with an IR thermometer and it was well north of 200 degrees at all times once warmed up.

TFI relocation 1.jpg

TFI relocation 2.jpg

TFI relocation 3.jpg
 

rednotch

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www.cardomain.com
  1. New Motorcraft replacement.
  2. Old Motorcraft, most likely original to the distributor.
  3. Generic Parts store replacement.
  4. A remote mount unit from a 7.5L F-350 (I'm going to try and make my own remote TFI one day).
  5. Module that came with a Cardone rebuilt distributor.
  6. Wells branded replacement.


1. New Motorcraft replacement:
TFI 1 New Motorcraft.jpg


2. Old Motorcraft:
TFI 2 Old Motorcraft.jpg


3. Parts store replacement:
TFI 3 Parts store replacement.jpg


4. Remote TFI from F-350:
TFI 4 Remote unit.jpg


5. Module that came with the Cardone distributor:
TFI 5 Cardone.jpg


6. Wells branded replacement:
TFI 6 Wells.jpg
don't feel bad I have more but I've owned mustangs since the 90's. the motorcraft they still sell. is made by SMP, standard motor Products easy to tell just looking at the cover, only one who uses that style. How old is the wells? Only option to get them here now is auto zone. duralast brand made by wells. used to be my go to but I think they changed the design again when NGK bought them up. I have a new one from there I'll see if I can snag a pic of. you'll notice all the newer ones ae missing that "thick film" part lol. filko used to make a good one until smp bought them out
 
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LX Dave

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Jul 2, 2017
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Back when I had the '87, I had a new Motorcraft one fail at an intersection once, blocking traffic. Talk about embarrassing. Since then I've gotten a bunch of older ones from random vehicles at the scrap yard. Out of 12+ that I got, I only got 1 that was bad. All the others were good, so now I have a bag full of the older good ones for future use. Also did a remote mount right after that new one failed and never had another problem.
 
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Mustang5L5

Put lubricant all over the balls
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Back in the early 2000s, anytime I was at a junkyard and say a grey TFI on a car, I snagged them.

Gave away a bunch to friends, have a couple spares for myself. Believe it or not, I’m still on my original TFI unless it was swapped before I got the car (~45k miles, circa 1997)
 
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rednotch

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www.cardomain.com
Back when I had the '87, I had a new Motorcraft one fail at an intersection once, blocking traffic. Talk about embarrassing. Since then I've gotten a bunch of older ones from random vehicles at the scrap yard. Out of 12+ that I got, I only got 1 that was bad. All the others were good, so now I have a bag full of the older good ones for future use. Also did a remote mount right after that new one failed and never had another problem.
yeah I try to grab the old motorcraft distributor mount ones if I see them in a u pull it just for the oem look and ease of using a factory tfi connector as the jumper when relocating them.. gut the board, solder the three jumpers then pot it and pop the cover back on, grab a ford heat sink and the wiring from a remote mount car, trim the heat sink for the distributor style tfi,, clean the harness up and you got, cheap relocation kit that unplugs from the distributor side ust like factory. screwing around with spade connectors at the pip all ways got on my nerves , Not a fan of the way mccullyracing wired his Mk3 kt but I guess its for people not comfortable with wiring to have more placement options

the newer motorcraft ones made by SMP I've had bad luck with when distributor mounted.
 

Dan02gt

mazing how much gas smell came from that tiny hole
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Back when I had the '87, I had a new Motorcraft one fail at an intersection once, blocking traffic. Talk about embarrassing. Since then I've gotten a bunch of older ones from random vehicles at the scrap yard. Out of 12+ that I got, I only got 1 that was bad. All the others were good, so now I have a bag full of the older good ones for future use. Also did a remote mount right after that new one failed and never had another problem.
Mine died on me this past summer driving almost 50 MPH. Car just cut off!! I was fortunate that traffic was light and I was able to get over to the outside lane and coast into a parking lot. After about 15-20 minutes with the hood popped it started up and I was able to drive home. Mine had an old looking Motorcraft on it. I relocated it with the MK3 kit and installed a new Delphi but I noticed the tach would jump weird when I started the car and I had an occasional miss-fire. I replaced it with a new Motorcraft and all is good.
 
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Mustang5L5

Put lubricant all over the balls
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Pulled apart one of my old Motorcraft TFIs. Similar to the other old MC units posted.

I have a 90s era Aftermarket I’ll pull apart later. I assume it's late 90's because I took it off a junkyard car around the year 2000

FCDBB088-40B6-4C3D-8575-3E9F63ADBF42.jpeg
 
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